Microbiology and Immunology 2500A/B Lecture Notes - Lecture 10: Mycobacterium Bovis, Pasteurization, Cell Envelope
18 Mar 2020
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Document Summary
Humans can be infected by ingestion of unpasteurized milk, leading to extrapulmonary tb: avium. Cause tb-like illness in humans, particularly in aids (immunocompromised) patients: leprae. Infection of m. tuberculosis can be latent or active. Latent: infection contained in lung; can"t spread (not transmitting) 2b people (1/4 of the world"s population) has latent tb. 10% of those with latent tb will develop active tb later in life. Latent tb is more common in areas of lower gdp. Slow generation time (>15 hrs), so hard to study. Unusual cell envelope with high concentrations of mycolic acid (waxy) Lethal oxidative stress promoting survival inside of macrophages. Impermeable to stains and dyes (due to wax) Acid fast stain: gram + but doesn"t stain (hallmark of mycobacteria) Acid fast is stained with carbol-fuchsin dye with slow heating (melts wax) Transmission from inhalation of droplets from infected host. Coughing/sneezing can generate 3000 droplet nuclei; each nuclei contain.
